/Engine/Source/Runtime/Experimental/Iris/Core/Public/Iris/Serialization/NetBitStreamReader.h
Reads BitCount bits and stores them in Dst, starting from bit offset 0. The bits will be stored as they are stored internally in this class, i.e. bits will be written from lower to higher memory addresses. If the BitCount exceeds the remaining space no bits will be written to Dst and the stream will be marked as overflown. It's up to the user to check for overflow.
void ReadBitStream ( uint32 * Dst, uint32 BitCount )